A wobble plate compressor includes a cylinder block having a plurality of cylinder bores, a plurality of pistons for reciprocating within the respective cylinder bores, a cylinder head secured to an end face of the cylinder block via a valve plate, and a plurality of inlet valves for opening and closing a plurality of inlet ports formed through the valve plate.
Within the cylinders are formed compression chambers, respectively, and the volume of each compression chamber varies with the motion of a piston associated therewith.
The cylinder head has a suction chamber formed therein for receiving low-pressure refrigerant gas flowing therein from an evaporator side.
The number of the inlet valves and the number of the inlet ports formed through the valve plate are equal to the number of the cylinder bores, similarly to the number of the compression chambers and the number of the pistons.
The suction chamber communicates with the compression chambers via the inlet ports.
During the suction stroke, as the volume of a compression chamber progressively increases, the inlet valve is bent toward the compression chamber side to open the inlet port, via which refrigerant gas in the suction chamber is drawn into the compression chamber.
FIG. 12 is a fragmentary enlarged plan view of a valve plate of a conventional wobble plate compressor.
A valve plate 702 is formed with inlet ports 715, and outlet ports 716 are formed inward of the inlet ports 715 (radially inward in the valve plate 702). Further, the inlet ports 715 and the outlet ports 716 are located inward of respective opening edges 706a of the cylinder bores. An inlet valve 721 is formed with a hole 763, such that the outlet port 716 is prevented from being closed by the inlet valve 721.
The opening edge 706a of the cylinder bore is formed with a stopper recess 770 at a location opposed to an end portion 721a of the inlet valve 721.
As the piston moves toward the bottom dead center position during the suction stroke, the difference in pressure between the compression chamber and the suction chamber is increased, whereby the inlet valve 721 is bent toward the compression chamber side to open the inlet port 715, via which refrigerant gas in the suction chamber is drawn into the compression chamber. At this time, the end portion 721a of the inlet valve 721 abuts on the stopper recess 770, which limits the bend of the inlet valve 721.
The dimension of depth of the stopper recess 770 (length from an end face of the cylinder block to the bottom surface of the stopper recess 770) is configured to be small to thereby reduce the suction pulsation.
As the piston moves toward the top dead center position during the compression stroke, the volume of the compression chamber is progressively reduced to increase the pressure in the compression chamber. At this time, the inlet valve 721 is brought into intimate contact with the valve plate 702 by high pressure to close the inlet port 715.
However, if the dimension of depth of the stopper recess 770 is small, the suction efficiency is lowered, which degrades the performance of the refrigerant compressor.
To improve the performance of the refrigerant compressor, it is necessary to increase the area of an opening formed during suction of refrigerant. To meet this requirement, it is necessary to increase the area of the inlet port 715. If the area of the inlet port 715 is increased, it is necessary to enlarge the inlet valve 721 accordingly.
However, if the area of the inlet port 715 is increased, during liquid compression in which liquid (liquid refrigerant) is compressed within the compression chamber, excessive load is applied to the inlet valve 721, which sometimes causes leakage of the liquid into the suction chamber side, or deformation or breakage of the inlet valve 721.
It is an object of the invention to provide a reciprocating refrigerant compressor that is capable of increasing the ar as of inlet ports, and at the same time preventing leakage of liquid into the suction chamber side and deformation and breakage of inlet valves.